Add regression test for $this narrowing to never inside isset()-guarded boolean decomposition#5840
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…uarded boolean decomposition - Adds tests/PHPStan/Analyser/nsrt/bug-14804.php reproducing the reported case verbatim from the issue's container code: an outer `$enum === X && isset($this->prop[$key])` guard followed by an inner `isset($this->other[$key])` block and a nested `if ($enum === X)`, where `$this` was incorrectly narrowed to `*NEVER*`. - The test asserts `$this` keeps its `$this(Bug14804\Container)` type both before and inside the nested narrowing, and that `$lifecycle` stays the full enum union. - The root fix already lives in ConditionalExpressionHolderHelper: the boolean-decomposition holder that collapsed an expression to `NeverType` (an artifact of the cross-kind holder + isset() truthy/falsey swap) is skipped. Verified the new test fails with `*NEVER*` when that guard is removed and passes with it. - Probed analogous constructs (empty(), array_key_exists(), `??`, BooleanOr early returns, static properties, narrowing non-`$this` locals and match results, and deeper nesting) — all already handled by the shared guard, no residual bug.
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Summary
PHPStan 2.2.2 introduced a regression where, inside an
if (isset($this->prop[$key]))block that followed an earlier compound
if ($enum === X && isset($this->other[$key]))guard,
$thiswas narrowed to*NEVER*. This marked the rest of the block unreachableand produced cascading false positives such as
Cannot access offset *NEVER* on mixed.The root cause was already fixed on the
2.2.xbranch (thenever-narrowing guard inConditionalExpressionHolderHelper). This change adds the missing regression test thatcaptures the exact reproduction from the issue and proves the family of cases is covered.
Changes
tests/PHPStan/Analyser/nsrt/bug-14804.php, a faithful copy of the containerresolve()method from the issue, asserting that$thiskeeps its$this(Bug14804\Container)type before and inside the nestedif ($lifecycle === Lifecycle::PERSISTENT)block, and that
$lifecyclestaysLifecycle::PERSISTENT|Lifecycle::TRANSIENT.Root cause
The cross-kind conditional-expression holders created when decomposing a
BooleanAnd/BooleanOrcondition containingisset()could compute a holder typethat collapses to
NeverType(e.g. removing a non-nullable property's full type afterthe isset() truthy/falsey swap). Applying such a holder in a later scope narrowed an
unrelated expression — here
$this— tonever, marking the whole scope unreachable.ConditionalExpressionHolderHelpernow skips any holder whose computed narrowing isNeverTypewhile the original expression type is notnever, since that result is anartifact rather than a real contradiction. The guard lives in the shared helper, so it
covers instance/static properties,
isset()/empty(), and both theBooleanAnd(false context) and
BooleanOr(true context) paths.Test
tests/PHPStan/Analyser/nsrt/bug-14804.phpreproduces the reported bug. It fails withActual: *NEVER*when theNeverTypeguard inConditionalExpressionHolderHelperisremoved and passes with it in place.
empty(),array_key_exists(),??,BooleanOrearly returns, static properties, narrowing non-$thislocals andmatchresults, and deeper nesting — and confirmed each is already correctly handled by the
shared guard, so no further source change is required.
Fixes phpstan/phpstan#14804